Evaporator unit



M 1 1957 "A. R. COSTANTINI ETAL 3,320,405

EVAPORATOR UNIT 2 Sheets-Sheet 1 Filed July 28, 1964 INVENTOR HNTHON Y RCosT'h NT! N! A N'T'HONY D W5 ATTORNEY ,May 16, 1967 A CZOSTANTINI ETAL 3,320,405

EVAPORATOR UNI T 2 Sheets-$heet 2 Filed July 28, 1964 ATTORNEY United States Patent 3,320,405 EVAPORATOR UNIT Anthony R. Costantini, Lafayette Hill, and Anthony Di Angelus, Manoa, Pa., assignors to Victory Metal Manufacturing Company, Plymouth Meeting, Pa., a corporation of Pennsylvania Filed July 28, 1964, Ser. No. 385,748 Claims. (Cl. 219-271) This invention relates generally to moisture vaporizing apparatus, and more particularly relates to apparatus for vaporizing moisture accumulated by the action of cooling coils employed in refrigeration devices to thereby dispose of condensed water vapor by passing the same back into the atmosphere exterior to the refrigerating device, and hence eliminates the need for providing a waste-water drain normally employed to carry off the condensation to a plumbing system.

A primary object of this invention is to provide a novel evaporator apparatus adapted for use with a refrigerating device which materially simplifies the installation of the latter by making it unnecessary to provide a water run-off drainage system as is normally employed to carry off water vapor condensed by the refrigerating device during operation thereof.

Another object of this invention is to provide a novel moisture vaporizing apparatus which may be installed directly in a refrigerating apparatus during construction thereof or subsequent thereto, which evaporator unit includes a water receiver having a heater disposed therewithin which vaporizes water collected within the receiver, and in which the heater device is automatically activated and deactivated by thermostatically controlled means.

Still another object of this invention is to provide a novel evaporator unit as aforesaid which is so installed within a refrigerating device that the vaporized water is removed from the refrigerating device and prevented from entering the refrigerated regions of the refrigerator.

The foregoing and other objects of the invention will appear more clearly hereinafter from a reading of the following specification in conjunction with an examination of the appended drawings, wherein:

FIGURE 1 is a perspective view of the novel evaporator unit according to the invention as seen from above and illustrating external details thereof;

FIGURE 2 is a vertical section, on an enlarged scale, taken through the evaporator unit of FIGURE 1 as would be seen when viewed along the lines 22 of FIGURE 1;

FIGURE 3 is an exploded perspective view of the parts of the evaporator unit which together control the operation of the water receiver heater structure, some parts being shown only fragmentarily;

FIGURE 4 is a horizontal sectional view taken through the water receiver of FIGURE 1 as would be seen when viewed along the lines 4-4 of FIGURE 2;

FIGURE 5 is an end view of the thermostat control and wiring assembly of the evaporator unit as would be seen when viewed along the line 55 of FIGURE 4;

FIGURE 6 is a view similar to that of FIGURE 5 but with a modification to the electrical circuit wiring;

FIGURE 7 is an enlarged fragmentary detail view of the structural arrangement by which the water receiver heater is mounted thereto, as would be seen when viewed along the line 77 of FIGURE 4;

FIGURE 8 is an enlarged fragmentary view of the water receiver condensate inlet pipe and its organization within the water receiver, as would be seen when viewed along the line 88 of FIGURE 4; and

FIGURE 9 is a schematic diagram of the electrical circuit of the evaporator unit.

In the several figures, like elements are denoted by like reference characters.

Referring now to the figures, and firstly to FIGURES 1, 2, 4 and 8, it is observed that the water receiver designated generally as 10 is formed from an open-topped rectangular pan 11 provided at its upper edge with a peripherally extending flange 12, and a cover plate 13 formed at its rear edge with an upturned mounting flange 14 which latter is provided, as at 15, with mounting apertures by means of which the entire device may be secured to a convenient mounting bracket or wall. The flange 12 and cover plate 13 are peripherally sealed completely thereabout by sealing compound 16 to form a water tight joint, and are secured together by sheet metal screws 17.

The water receiver pan 11 is fitted with the condensate inlet pipe 18 secured to and opening into the pan 11 through an end wall 19 proximate to the lower region of the latter, the inlet opening of the condensate pipe 18 lying just above the bottom of the pan 11 so that it is always completely beneath the surface level of the condensate water within the receiver, as is most clearly seen from the showing of FIGURE 8. The top cover plate 13 is fitted with a short vent stack 20 through which the vaporized condensate leaves the water receiver 10. The electrical assembly, including the thermostat for controlling the water receiver element, and the electrical connections thereto are carried by the near end wall 19 of the water receiver 10 and are enclosed within the removable housing or cover 21.

As best seen in FIGURES 2, 4 and 7, extending in a horizontal plane within the pan 11 at a level higher than the discharge opening of the condensate pipe 18 is a U-shaped heater element 22 having threaded terminal ends 23 of electrical insulating material projected through holes in the near end wall 19 of the pan 11, and upon which are threaded the nuts 24 which fixedly secure the heater element 22 to the pan 11 in the manner illustrated. The U-shaped heater element 22 may be of the Chromolox type manufactured by Edwin L. Weigand and Company of Pittsburgh, Pennsylvania. Such heaters have an outer Inconel sheath within which extends an electrically energizable heater element which is electrically but not thermally insulated from the sheath by a magnesium oxide powder, and which extends outward through the terminal ends of the heater element as shown at 25 in FIGURE 7 to electrically conductive terminals 26 carrying connecting screws 27.

Bridging between the arms of the heater element 22 is a copper heat transfer plate 28 having its side edges curved around and under the heater element arms, as at 29, so that the transfer plate 28 is in intimate mechanical and thermal contact with the heater element. The end of the copper heat transfer plate 28 proximate the near end wall 19 of the pan 11 is turned upward to provide a flange 30. Disposed between the heat transfer plate flange 30 and the end wall 19 is a gasket 31 centrally circularly apertu red as at 32, and disposed against the opposite face of the heat transfer plate flange 30 is the heat exchanger mounting plate 33. Disposed on the outside face of the pan end wall 19 is a mounting plate 34 provided with a central circular hole 35 for mounting to the end wall of the pan 11 the thermostat designated generally as 36.

Each of the end flange 3t), gasket 31, heat exchanger mounting plate 33, thermostat mounting plate 34, and pan end wall 19 and thermostat 36 are provided with a plurality of alignable holes through which are projectable a pair of long machine screws 37 and a pair of short machine screws 38 upon which are threaded the nuts 39 and 40 effective to compress and clamp together all of these elements into a rigidly secured structure. The long machine screws 37 are of sufficient length to project through holes in the end of the thermostat cover 21 to have threaded thereupon cap nuts 41 which serve to clamp the cover 21 securely in position. The pan end wall 19 is also circularly apertured as at 42, and the apertures 32, 35 and 42 of the gasket 31, thermostat mounting plate 34 and the end wall 19 are concentric in the clamped together arrangement, with the aperture 32 of the gasket 31 being of somewhat smaller diameter than the apertures 35 and 42, as is most clearly seen in the showing of FIGURE 4.

Disposed within the circular aperture 32 of the gasket 31 is a circular metal heat transfer plate or disc 43 whose outer face is in fiat surface contact with the thermostat thermal contact face 44, and whose inner face is in flat surface contact with the end flange 30 of the copper heat transfer plate 28. The heat transfer disc 43 is made of stainless steel and provides a thermal lag in the heat transfer between the copper plate 28 and thermostat 36 which prevents undesired electrical cycling of the apparatus, as will become clear hereinafter. As also best seen in FIG- URE 4, the diameter of the heat transfer disc 43 is sufiiciently smaller than the apertures 35 and 42 to prevent contact with the pan end wall 19 and thermostat mounting plate 34 to thereby prevent heat transfer from the disc 43 to the water receiver pan 11. The gasket 31 also prevents heat transfer to the receiver pan from the copper heat transfer plate flange 30 and helps to provide a water seal when used in conjunction with the sealing compound 45 as seen in FIGURES 2 and 4.

As seen in FIGURES 4, 5, 6 and 9, and most clearly in FIGURES 5 and 9, the electrical connections of the evaporator unit are as follows. An electrical cable 46 is formed of two conductors 47 and 48, the conductor 47 being directly connected to one of the conductive terminals 26 of the U-shaped heater while the conductor 48 is connected to one contact 49 of the thermostat 36. The other terminal 26 of the heater 22 is connected via conductor 50 to thermostat contact 51. A thermostat heater element 52 is electrically connected between thermostat contact 49 and a terminal lug 53 carried by the thermostat, the terminal lug being itself electrically connected to the thermostat contact 51 by means of conductor 54. The electrical cable 46 is provided with a strain relief 55 at the point where it passes through the cover 21. The thermostat 36 includes internally therewithin a switch element 56 which bridges between and connects together the contacts 49 and 51 whenever the thermostat temperature is below approximately 184 Fahrenheit, and opens the electrical connection between the thermostat contacts 49 and 51 whenever the thermostat temperature rises to approximately 219 Fahrenheit.

Referring now to the schematic diagram of FIGURE 9 it will be seen that when the thermostat switch is open, the water receiver heater element 22 and the thermostat heater element 52 are in series with the line voltage. The thermostat heater 52 is of much higher electrical resistance than that of the water receiver heater 22 so that in this series connection the current which flows is determined by the resistance of the thermostat heater and is effective to produce a heating power of approximately 5 watts in the thermostat heater, the heat generated by heater 22 being under these circumstances negligible. When however the thermostat switch '56 closes, the high resistance thermostat heater element 52 is short circuited so that the line voltage is impressed directly across the water receiver heater element 22 alone, the current flowing under these conditions through the heater 22 generating approximately 600 watts in the heater. The thermostat heater resistance is therefore approximately times the resistance of the water receiver heater 22 so that when both are in series there is approximately only forty milliwatts dissipated by the receiver heater, this being negligible as previously pointed out.

The evaporator unit operates in the following manner. Assuming the water receiver 10 to be empty, and that the thermostat is at normal room temperature which is con siderably below the thermostat closing temperature of 184 Fahrenheit, the thermostat switch element 56 will be closed and the receiver heater 22 will be energized to thereby dissipate its 600 watts of heat. With no water in the receiver to dissipate the heat, heat is rapidly transferred from the heater 22 through the end flange 30 of the copper heat transfer plate 28, through the stainless steel transfer disc 43 to the thermostat 36 causing the temperature of the thermostat to begin an immediate rise until at approximately 219 Fahrenheit the thermostat switch 56 opens. The thermostat heater element 52 is therefore thrown into series with the water receiver heater 22, which for all intents and purposes effectively deenergizes the heater 22 while energizing the thermostat element 52. The temperature of the heater 22 therefore begins to drop immediately as do also the temperatures of the copper transfer plate 28 and flange 30 and heat transfer disc 43. The five watt dissipation of the thermostat heater element 52 prevents the thermostat temperature from dropping below 184 Fahrenheit so that the thermostat switch 56 remains open and the water receiver heater 22 remains in its substantially deenergized state.

As the refrigerating apparatus with which the evaporator unit is used functions, condensate water from the cooling coils flows downward from a collection point through the condensate pipe 18 and into the bottom of the water receiver 10. The condensate water is normally at a temperature in the range of 40 to 50 Fahrenheit which is considerably cooler than the 184 Fahrenheit plus temperature of the thermostat and heater 22 and heat transfer plate 28. As the condensate water level rises within the water receiver 10, it first seals the open bottom end of the condensate inlet pipe 18 and then con tinues to rise until it makes contact with the heater 22 and heat transfer plate 28. The relatively low temperature of the water thus acts as a heat sink for the relatively higher temperature of the heater 22 and heat transfer plate 28. Consequently heat begins to flow from the heat transfer plate and heater 22 into the cool condensate which is now immersing the heater and heat transfer plate.

The five watt heating capacity of the thermostat heater 52 is insufficient to maintain the thermostat temperature above 184 Fahrenheit when it is also called upon to provide the heat which is being extracted from the heat transfer plate by the cold condensate. The thermostat temperature thus drops below 184 Fahrenheit and the thermostat switch 56 closes to thereby energize the water receiver heater 22. The high heat generation capacity of the heater element 22 raises the temperature of the cold condensate in the water receiver until it eventually reaches the boiling point at 212 Fahrenheit. The condensate thus begins to boil off with the vapor leaving the water receiver through the vent stack 20. The boiling rate is chosen to be greater than the maximum anticipated rate of formation of cold condensate so that the water in the receiver 10 begins to fall in level until it drops just below the heater 22 and heat transfer plate 28, being nevertheless still sufliciently high to provide a water seal for the lower end of the condensate pipe 18 and prevent vapor from travelling backward up through the condensate pipe and into the refrigerating apparatus.

With the heater 22 and heat transfer plate 28 no longer Within the water in the receiver, their temperature begins to rise. This temperature rise is transferred to the thermostat 36 through the heat transfer plate flange 30 and stainless steel transfer disc 43, the latter acting as a heat lag or delay element which prevents the temperature at the thermostat itself from rising to 219 Fahrenheit until the water in the receiver has cleared the heater element and transfer plate. As soon as the thermostat temperature reaches the 219 point, the thermostat switch 56 opens to again effectively deenergize the water receiver heater 22 and energize the thermostat heater element 52. The system temperature again begins to drop but remains above 184 so long as no additional condensate enters the Water receiver.

When now additional condensate flows into the water receiver 10, the water level will of course again begin to rise until it immerses the heater 22 and heat transfer plate 28. However, since the water which was originally in the water receiver is relatively hot, a considerable amount of cold, condensate will be required in order to bring the water temperature down to a point sufficient to again drop the thermostat temperature below 184 and cause the switch 56 to again close and energize the water receiver heater 22. For this reason, the water receiver pan 11 is sufficiently deep to accommodate the maximum possible water level rise above the heating element 22.

The system will continue to cycle in the aforedescribed manner as determined by the rate of formation of cold condensate. Excessively frequent cycling is prevented by the presence of the heat transfer disc 43 which provides for a lag in heat transfer between the copper heat transfer plate 28 and the thermostat thermal contact face 44.

. Thus, this results in a higher water level in the receiver than would otherwise be the case before energization of the water receiver heater 22 occurs, and similarly results in a lower water level in the receiver at the point at which the water receiver heater 22 is effectively deenergized. Should the anticycling function of the thermostat heater 52 not be desired, the thermostat heater element 52 may i be disabled in the manner illustrated in the showing of FIGURE 6 by merely removing, or not initially installing, the conductor wire 54. The showing of FIGURE 6 is otherwise the same as that of FIGURE 5.

Having now described our invention in connection with a particularly illustrated embodiment thereof, it will be the essential scope or spirit of our invention, and accordingly it is intended to claim the same broadly as well as specifically as indicated by the appended claims.

What is claimed as new and useful is:

1. An automatic temperature operated evaporator device, comprising in combination,

(a) a liquid receiver having an inlet opening thereto proximate to the bottom thereof, and a liquid vapor outlet therefrom proximate to the top thereof,

(b) an electrically energizable heater element mechanically supported by and disposed within said liquid receiver above the elevation of the receiver inlet opening, said heater element being electrically and substantially thermally insulated from direct contact with said liquid receiver and having electrical energization terminals projecting externally of the receiver for connection to a source of electrical energy,

(0) a thermally highly conductive heat transfer plate mechanically intimately secured to said receiver heater in broad area contact therewith for good heat transfer therebetween to thereby increase the effective area of heat transfer between the liquid in said receiver and said heater element, said heat transfer plate having a flange portion positioned adjacent to an aperture in a wall of said receiver which flange is thermally insulated from said receiver by an intervening liquid tight gasket preventing escape of liquid from said receiver through said Wall aperture,

((1) a thermostat including (1) switch means carried by said liquid receiver externally thereof including a pair of electrical contacts connected in series with said heater element by means of said heater terminals and conductor means adapted for connection to a source of electrical energy, said thermostat controlling said switch means so that the electrical contacts thereof open at a first predetermined thermostat temperature higher than the boiling point of water and close at a second predetermined thermostat temperature lower than the boiling point I of water,

(2) and a thermal contact face thermally coupled to the flange portion of said heat transfer plate of said energizable heater element through said receiver wall aperture.

2. An automatic temperature operated evaporator device, comprising in combination,

(a) a liquid receiver having an inlet opening thereto proximate to the bottom thereof, and a liquid vapor outlet therefrom proximate to the top thereof,

(b) an electrically energizable heater element mechanically supported by and disposed within said liquid receiver above the elevation of the receiver inlet opening, said heater element being electrically and substantially thermally insulated from direct contact with said liquid receiver and having electrical energization terminals projecting externally of the receiver for connection to a source of electrical energy,

(0) a thermally highly conductive heat transfer plate mechanically intimately secured to said receiver heater in broad area contact therewith for good heat transfer therebetween to thereby increase the eifective area of heat transfer between the liquid in said receiver and said heaterelement, said heat transfer plate having a flange portion positioned adjacent to an aperture in a wall of said receiver which flange is thermally insulated from said receiver by an intervening liquid tight gasket preventing escape of liquid from said receiver through said wall aperture,

(d) a thermostat including (1) switch means carried by said liquid receiver externally thereof including a pair of electrical contacts connected in series with said heater element by means of said heater terminals and conductor means adapted for connection to a source of electrical energy, said thermostat controlling said switch means so that the electrical contacts thereof open at a first predetermined thermostat temperature higher than the boiling point of water and close at a second predetermined thermostat temperature lower than the boiling point of water,

(2) a thermal contact face thermally coupled to the flange portion of said heat transfer plate of said energizable heater element through said receiver wall aperture,

(e) and thermal delay means physically interposing and contacting said thermostat thermal contactface and the said flange portion of said heat transfer plate effective to slow the rate of heat transfer therebetween.

3. An automatic temperature operated evaporator device, comprising in combination,

(a) a liquid receiver having an inlet opening thereto proximate to the bottom thereof, and a liquid vapor outlet therefrom proximate to the top thereof,

(b) an electrically energizable heater element mechanically supported by and disposed within said liquid receiver above the elevation of the receiver inlet opening, said heater element being electrically and substantially thermally insulated from direct contact with said liquid receiver and having electrical energization terminals projecting externally of the remostat temperature lower than the boiling point of water,

(2) and a thermal contact face thermally coupled to the flange portion of said heat transfer plate ceiver for connection to a source of electrical energy, 5 of said energizable heater element through said (c) a thermally highly conductive heat transfer plate receiver wall aperture,

mechanically intimately secured to said receiver (e) and a thermostat heater element electrically conheater in broad area contact therewith for good heat nected across the said switch contacts to generate heat transfer therebetween to thereby increase the effecto maintain the thermostat at a temperature higher tive area of heat transfer between the liquid in said than the said second predetermined temperature to receiver and said heater element, said heat transfer thereby maintain the thermostat contacts open after plate having a flange portion positioned adjacent to the thermostat temperature has once risen to the an aperture in a wall of said receiver which flange is said first predetermined temperature, said thermostat thermally insulated from said receiver by an intervenheater being effective so long as it generates heat at ing liquid tight gasket preventing escape of liquid a rate higher than that removed by the thermal mass from said receiver through said wall aperture, of low temperature liquid in said receiver. (d) a thermostat including 5. An automatic temperature operated evaporator de- (I) switch means carried by said liquid receiver vice, comprising in combination,

externally thereof including a pair of electrical (a) a liquid receiver having an inlet opening thereto contacts connected in series with said heater proximate to the bottom thereof, and a liquid vapor element by means of said heater terminals and outlet therefrom proximate to the top thereof, conductor means adapted for connection to a (b) an electrically energizable heater element mech- SOllfee 0f electrical y, Said thermostat eOIlanically supported by and disposed within said liquid trolling Said Switch means 50 that the electrical receiver above the elevation of the receiver inlet contacts thereof Open a a first predetermined opening, said heater element being electrically and thermostat temperature hlgher than the boiling substantially thermally insulated from direct con- Polht of Water and Close at a Second Pfedeteftact with said liquid receiver and having electrical mined thermostat temperature lower than the energization terminals projecting externally of the boiling point of water, receiver for connection to a source of electrical (2) a thermal contact face thermally insulated energy,

fr direct Contact With Said receiver and ther' (c) a thermally highly conductive heat transfer plate mally coupled to the flange Pertleh of said heat' mechanically intimately secured to said receiver heattrahsfer Plate of said eherglztlble heater element er in broad area contact therewith for good heat through Saltl reeelvel Wall ep transfer therebetween to thereby increase the effecand thermal delay means p y y lhtetposlng and tive area of heat transfer between the liquid in said eontaetihg sa1d thermostat thetmal Contact face and receiver and said heater element, said heat transfer the Said flange Portion of said heat transfer Plate plate having a flange portion positioned adjacent to elleetlve Slow the fate of heat ttatlstel' there an aperture in a wall of said receiver which flange h sa1d thermal delay means belllg thermally is thermally insulated from said receiver by an interinsulated from dlrect contact with said receiver. 40 vening liquid tight gasket preventing escape f liquid 4. An automatic temperature operated evaporator def Said receiver through Said n aperture, Vlee pt h lh cemblnatlfmi (d) a thermostat including (a) a ttquld tecetver havmg an Inlet t thereto (1) switch means carried by said liquid receiver proxlmate to the bottcim thereof and a fvapor externally thereof including a pair of electrical outlet thertafrom proximate to the top t ereo contacts connected in series with said heater (b) an electrically energizable heater element mechan- 1 t b a f h 1 d ically supported by and disposed within said liquid came y Imam O Sal eater termlpas an receiver above the elevation of the receiver inlet conductor t adapted connectlon to a opening, said heater element being electrically and souffle of tlectrtcal energy sa1d thermostat P susbtantially thermally insulated from direct contact tlolllng sa1d Swltch means so that the electt'lcal with said liquid receiver and having electrical ener- Contacts thereof Open at a first Ptetletermlhed gization terminals projecting externally of the rethermostat temperature higher than the boiling ceiver for connection to a source of electrical energy, point of water and close "at a second predeter- (c) a thermally highly conductive heat transfer plate mined thermostat temperature lower than the mechanically intimately secured to said receiver b ilin oint of te heater in broad area contact therewith for good heat (2) a h l Contact f h ll i l d transfer therebetween to thereby increase the eifecf direct Contact with said receiver and t1ve area of heat transfer between the liquid in said thermally Coupled to the flange portion of Said receiver and sa1d heater element, s a1d heat transfer heat transfer plate of Said energizable heater plate havmg flange porno? poslttoned atllacent to 0 element through said receiver wall aperture, i aperture 9 Wall of Sand t Whlch flan-g6 (e) and thermal delay means physically interposing is thermally insulated from said receiver by an mtervening liquid tight gasket preventing escape of and contacting said thermostat thermal contact face liquid from said receiver through said wall aperture, and h sa1d flange Pomon of sa1d heat Hamster Plate ((1) athermostat including effective to slow the rate of heat transfer therebe- (l) switch means carried by said liquid receiver t sa1d thettnal delay means btitng thermally externally thereof including a pair of electrical insulated from dlrect contact with sa1d receiver, contacts connected in series with said heater eleand a thermostat heater element electrically e011- ment by means f said heater i b and nected across the said switch contacts to generate ductor means adapted for connection to a source e to maintain t thermostat at e temperature of electrical energy, said thermostat controlling h gl r than the sa1d second predetermined temperasaid switch means so that the electrical contacts tul'e to thereby malhtalh the thermostat contacts p th f Open at a fi t predetermined h tat after the thermostat temperature has once risen to temperature higher than the boiling point of the said first predetermined temperature, said thermowater and close at a second predetermined 'therstat heater being effective so long as it generates heat at :1 rate higher than that removed by the thermal mass of low temperature liquid in said receiver.

References Cited by the Examiner UNITED STATES PATENTS Stranszky 219 -330 10 10 2,437,262 3/1948 Levitt et a1. 219328 X 2,565,638 8/1951 Victory 21944-1 3,144,547 8/1964- Price Z19441 FOREIGN PATENTS 780,006 7/1966 Great Britain.

RICHARD M. WOOD, Primary Examiner.

C. L. ALBRITTON, Assistant Examiner. 

1. AN AUTOMATIC TEMPERATURE OPERATED EVAPORATOR DEVICE, COMPRISING IN COMBINATION, (A) A LIQUID RECEIVER HAVING AN INLET OPENING THERETO PROXIMATE TO THE BOTTOM THEREOF, AND A LIQUID VAPOR OUTLET THEREFROM PROXIMATE TO THE TOP THEREOF, (B) AN ELECTRICALLY ENERGIZABLE HEATER ELEMENT MECHANICALLY SUPPORTED BY AND DISPOSED WITHIN SAID LIQUID RECEIVER ABOVE THE ELEVATION OF THE RECEIVER INLET OPENING, SAID HEATER ELEMENT BEING ELECTRICALLY AND SUBSTANTIALLY THERMALLY INSULATED FROM DIRECT CONTACT WITH SAID LIQUID RECEIVER AND HAVING ELECTRICAL ENERGIZATION TERMINALS PROJECTING EXTERNALLY OF THE RECEIVER FOR CONNECTION TO A SOURCE OF ELECTRICAL ENERGY, (C) A THERMALLY HIGHLY CONDUCTIVE HEAT TRANSFER PLATE MECHANICALLY INTIMATELY SECURED TO SAID RECEIVER HEATER IN BROAD AREA CONTACT THEREWITH FOR GOOD HEAT TRANSFER THEREBETWEEN TO THEREBY INCREASE THE EFFECTIVE AREA OF HEAT TRANSFER BETWEEN THE LIQUID IN SAID RECEIVER AND SAID HEATER ELEMENT, SAID HEAT TRANSFER PLATE HAVING A FLANGE PORTION POSITIONED ADJACENT TO AN APERTURE IN A WALL OF SAID RECEIVER WHICH FLANGE 